/ok'ul tay"sheuhn/ , n.
1. Astron. the passage of one celestial body in front of another, thus hiding the other from view: applied esp. to the moon's coming between an observer and a star or planet.
2. disappearance from view or notice.
3. the act of blocking or hiding from view.
4. the resulting hidden or concealed state.
[ 1375-1425; late ME occultation- (s. of occultatio ) a hiding, equiv. to occultat ( us ) (ptp. of occultare to conceal, keep something hidden, freq. of occulere; see OCCULT) + -ion- -ION ]